CEM 142: FINAL EXAM
66 Cards in this Set
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decreases
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atomic radius ______ L-->R across the periodic table
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absorbed from
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when a bond breaks, energy is ____________ the surroundings
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released to
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when a bond is formed, energy is ___________ the surroundings
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electromagnetic attraction
AND
electromagnetic repulsion
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on a PE graph, as the atoms move closer, the __________________ is strongest
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how much energy would be needed to overcome the interaction
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the depth of the PE will tell you...
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removed from the system
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in order for 2 H molecules to bond, energy must...
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London dispersion forces
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temporary fluctuating dipoles
depends on size, surface area, and shape of molecule
present in all substances
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LDF
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for non-polar molecules, _____ is the only force present
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dipole-dipole forces
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present in polar substances
uneven distribution of e-
permanent dipole
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hydrogen bonding
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present in compounds with H covalently bonded to O, N or F
bond is highly polarized
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LDF, D-D, H-B
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order of intermolecular forces, weakest to strongest
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4
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Carbon "likes" to form ____ bonds
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2
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Oxygen "likes" to form ____ bonds
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First Law of Thermodynamics
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energy can neither be created nor destroyed
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enthalpy (H)
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the heat absorbed or emitted during a reaction under constant pressure
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endothermic
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ΔH(+)
when a system absorbs heat
work is done by the surroundings on the system
surroundings get cold
water melting is this
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exothermic
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ΔH(-)when a system releases heat
work is done by the system on the surroundings
surroundings get hot
water freezing is this
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q
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thermal energy change
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2nd Law of Thermodynamics
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for any change, the total entropy of the universe must increase
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entropy (S)
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a measure of the number of possible arrangements for a given state
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hot to cold
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the transfer of energy from _____ to _____ is simply more probable
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ΔSsys (-)
ΔHsys (-)
ΔHsurr (+)
ΔSsurr (+)
ΔSnet (+)
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Freezing (exothermic)
ΔSsys (?)
ΔHsys (?)
ΔHsurr (?)
ΔSsurr (?)
ΔSnet (?)
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ΔSsys (+)
ΔHsys (+)
ΔHsurr (-)
ΔSsurr (-)
ΔSnet (+)
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Melting (endothermic)
ΔSsys (?)
ΔHsys (?)
ΔHsurr (?)
ΔSsurr (?)
ΔSnet (?)
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ΔHvap
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the thermal energy change when a liquid boils
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ΔSuniv = ΔSsys + ΔSsurr
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ΔS univ = ______ + _______
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ΔH = TΔS
or
ΔS = ΔH/T
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relationship between ΔS and ΔH (when ΔG=0)
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1. momentary fluctuating of e- cloud
2. induces a distortion (dipole)
3. which induces another
4. causing an electrostatic attraction between the atoms
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why are two Ne atoms attracted to each other? (4 steps)
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increases
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if the total entropy __________, the change will happen
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decreases
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if the total entropy __________, the change will not happen
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ΔG = ΔH - TΔS
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Gibbs free energy equation
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never happens
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ΔG = ΔH - TΔS
(+) = (+) - (+)(-)
when does it happen?
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always happens
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ΔG = ΔH - TΔS
(-) = (-) - (+)(+)
when does it happen?
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happens with high temp
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ΔG = ΔH - TΔS
(-) = (+) - (+)(+)
when does it happen?
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happens with low temp
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ΔG = ΔH - TΔS
(-) = (-) - (+)(-)
when does it happen?
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molecules have more KE and move faster
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solutions tend to form faster in hot water because...
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saturated
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no more solute will dissolve
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unsaturated
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solute added will dissolve
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miscible
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solute and solvent mix up
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immiscible
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solute and solvent don't mix
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volumetric flask
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what type of glassware should be used when making a solution?
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M1V1 = M2V2
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relationship between 2 substances' molarities and volumes
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0
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when the temp is 273 K, what is ΔG?
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endo-
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breaking IMF's is ______thermic
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exo-
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forming IMF's is ______thermic
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(g solute)/(g solvent) *100
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% by mass equation
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10*10^-6
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a 10 ppm soln has ________ per gram
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10*10^-9
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a 10 ppb soln has _________ per gram
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ion-dipole force
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force between an ion and a polar molecule
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interactions in the products are stronger than the interactions in the reactants
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if the reaction is overall exothermic...
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interactions in the reactants are stronger than the interactions in the products
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if the reaction is overall endothermic...
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negative
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when something is soluble, ΔG will be ____________
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it would decrease the entropy of the system
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oil and water are immiscible because....
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antrophillic or amphipathic
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a molecule containing both a hydrophilic and hydrophobic end
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micelles
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organized clusters of amphipathic molecules (in aq. solns)
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clathrate
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lattice trapping molecules (in solid)
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PV = nRT
P: pressure
V: volume
n: # moles
R: constant
T: temp
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ideal gas equation
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Kr because it has a larger separation of charge
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which noble gas is most soluble in water? why?
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the dipole of water induces a dipole in O2 by distorting the O2 electron cloud
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explanation of oxygen dissolving in water
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increase
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when ΔG is negative, the entropy of the universe must __________
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they are more polarizable, resulting in stronger interactions with the water molecules
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larger gas molecules are more dissolvable in water because...
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the entropy of the system decreases and the entropy of the surroundings increases
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when liquid water freezes below 0 C...
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negative, because the number of positions available to the carbon dioxide molecules decreases
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the entropy change when CO2 dissolves in water is....
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an acid dissolves in water to give H+
OR
a base dissolves in water to give -OH
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Arrhenius acid-base model
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an acid is a proton donor (to a base)
a base is a proton acceptor
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Bronsted Lowery acid-base model
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H3O+
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conjugate acid of H2O
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OH
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conjugate base of H2O
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